Projects / 11/27/2025

At the heart of Malaysian justice

New roof and domes for one of the largest courthouse complexes in the world

Comprehensive waterproofing and refurbishment works were carried out on the domes and main roof of Kompleks Mahkamah Kuala Lumpur, one of the world’s largest courthouse complexes. The intervention included anti-corrosion priming, joint sealing, waterproofing with polyurea membranes and applying UV-resistant protective coatings, ensuring durability even on complex dome geometries.

Kompleks Mahkamah Kuala Lumpur is a large courthouse complex with colonial-inspired architecture that houses the High Court, the Sessions Court and the Magistrates’ Court of Kuala Lumpur. The U-shaped complex consists of six above-ground floors, the first five of which are occupied by courtrooms, while the sixth is reserved for administrative offices and surau, separate Muslim prayer rooms for men and women.

Architecturally, the complex is dominated by a central portico surmounted by a large dome, which in turn is surrounded by four smaller domes. The two side wings each have three further porticoes and four hemispherical domes, adding to the symmetry and grandeur of the building.

Kompleks Mahkamah Kuala Lumpur is a large courthouse complex with colonial-inspired architecture that houses the High Court, the Sessions Court and the Magistrates’ Court of Kuala Lumpur.

Analysis and critical issues

Several courtrooms were found to have experienced extensive leakages from rainwater from both the domes and the reinforced concrete roof in 2021. Despite repairs being carried out on the roof using various waterproofing membranes, the problem persisted. To address the issue, detailed analyses were carried out to identify a reliable and long-lasting solution. The investigations revealed that the joints between the aluminium sheets on the domes had deteriorated, allowing rainwater to seep in. The situation was further aggravated by water that had entered from the concrete roof decks located alongside the domes and the concrete deck above a plaza area.

To waterproof the metal domes, Primer Rustop EP was first applied and the joints were sealed with Mapeflex PU 45 FT and Mapeband SA, followed by spray application of Purtop 1000 polyurea membrane

A tried and tested solution

The success of previous waterproofing work carried out in 2019-2020 on the roof of the Syariah Courts of Justice in Kuala Lumpur using Mapei solutions convinced the owner to adopt the Purtop 1000 system once again for this new project. The first step in the treatment proposed for the aluminium domes was the application of Primer EP Rustop, an epoxy primer for metal surfaces with excellent anti-corrosion properties.

Next, the joints were sealed using Mapeflex PU 45 FT high-performance polyurethane sealant combined with Mapeband SA self-adhesive tape.

Purtop 1000 two-component, solvent-free pure polyurea waterproofing membrane was then sprayed on the domes and decks using a high-pressure bi-mixer type pump.

The flexibility of the membrane allowed it to adapt perfectly even to complex geometries on both new and existing buildings, and this together with its excellent tensile and tear strength and its excellent resistance to alkalis and diluted acids made it ideal for waterproofing a non-flat structure such as a dome. ù

Finally, Mapecoat CF-AP** coating was applied to ensure protection and resistance to UV rays, high temperature and abrasion.

After the domes, the next step was the roof

After completing the domes, the next stage was to waterproof the approximately 7,000 m² surface of the main roof. The first step involved removing damaged sections of reinforced concrete, after which the surfaces were cleaned mechanically to ensure effective bonding of the applied products. The substrate was treated with Primer SN mixed with Quartz 0.5 quartz sand, after which Mapefloor EP19 MT epoxy mortar** (distributed by Mapei Malaysia) was applied to level the surfaces and create a multilayer coating. Finally, the Purtop 1000 waterproofing membrane was sprayed onto the surface. As a result, the roofs of the entire complex are now fully waterproof and secure, delivering long-lasting protection against water infiltration and leakage.

The roof deck was treated with Primer SN mixed with Quartz 0.5, followed by the application of Mapefloor EP19 MT epoxy mortar** to level the surfaces.

Beyond the roofs

The waterproofing work also included one of the internal courtyards extending over an area of approximately 5,000 m². Following the application of Mapelastic waterproofing mortar (available on the international market as Mapelastic Zero*), the ceramic tiles were laid using Keraflex Maxi S1 Zero* high-performance cementitious adhesive. The joints were grouted with Keracolor FF water-repellent mortar.